1. Field of the Invention
The present invention relates to a recording apparatus recording an image.
2. Description of the Related Art
There is known a roller pair which performs registration of a recording medium such as a sheet material by making the recording medium along a guide surface as a reference wall. The roller pair includes a transport roller and an skew roller. A rotational shaft of the transport roller is perpendicular to the guide surface, and the transport roller transports the recording medium in a transport direction. The skew roller has an outer circumferential surface in a columnar shape. The skew roller rotates in association with the transport of the recording medium and has a rotational shaft which is inclined with respect to the rotational shaft of the transport roller so that the recording medium can be drawn to the side of the guide surface. This construction enables the registration of the recording medium.
There is also known an skew roller pair with a spur which performs the registration of the recording medium by making the recording medium along the guide surface. The spur is used for the skew roller pair with the spur, instead of the skew roller forming the above roller pair.
In the registration of the recording medium, the roller pair causes the skew roller to move the recording medium to the guide surface, even when the end surface of the recording medium is brought into contact with the guide surface. In this situation, although the thrust load is applied on the skew roller owing to the contact between the guide surface and the recording medium, the recording medium is easy to slide on the skew roller, in other words, the recording medium is more likely to move in a direction away from the guide surface. Thus, occurrence of a jam of the recording medium can be suppressed. However, the skew roller scrapes an image recorded on the recording medium when the recording medium slides on the skew roller, and thus any image defect problem may occur. Further, in the case that the image recorded on the recording medium makes contact with the skew roller, a recording material for forming the image is adhered to the outer circumferential surface of the skew roller, which may cause a problem that the recording material adhered to the skew roller is transferred to the recording medium to make the recording medium dirty.
Meanwhile, in the case that the spur is used instead of the skew roller as described above, since the spur has teeth each having a very small contact area with the recording medium as compared with the skew roller, it is possible to prevent the recording medium from getting dirty. However, the teeth of the spur function as spikes to stick in the surface of the recording medium in the registration of the recording medium. Thus, even when the thrust load is applied on the spur due to the contact between the guide surface and the end surface of the recording medium, the recording medium hardly slides on the spur. As a result, the jam of the recording medium may occur.